This invention involves heat insulation for building structures whereby the walls, roof, ceiling, floors and other wall structures of the building are insulated with sheets of radiant heat insulation, with or without additional layers of convection and/or conduction heat insulation. More particularly, this invention utilizes reflective sheet material such as metal foil in combination with a blanket having an array of air filled cells, for use alone or in combination with other heat insulation materials in wall structures for insulating the wall structures from the transfer of heat.
Heat insulation material placed in walls, ceilings, roofs, floors and other xe2x80x9cwall structuresxe2x80x9d typically comprise fibrous blanket insulation, such as elongated blankets formed of fiberglass. The principle of the blanket insulation is to form dead air spaces that provide insulation against convection and conduction heat transfer. The blanket insulation can be formed in small xe2x80x9cclumpsxe2x80x9d and blown into spaces such as into the attics of residential homes and other building structures, and can also be made into elongated blankets formed in a specific width and depth that is suitable for placement between parallel joists, studs, rafters, and other parallel support structures that are uniformly spaced apart. The elongated blanket, such as a fiberglass blanket, is cut to the desired length at the job site for placement between the parallel structures. Also, a sheet of facing material usually is applied to one broad surface of the blanket, with the facing material having overhanging edges extending beyond the sides of the blanket to form xe2x80x9ctabsxe2x80x9d that can be applied by the installer to studs, joists, etc. of the building structure to hold the blanket in place.
Fiberglass is one of the most desirable materials for forming blanket insulation because it holds its shape and traps a substantial amount of air between its fibers to form the dead air spaces. However, the fiberglass alone does not provide adequate heat insulation against radiant heat transfer.
In the recent past, an additional sheet of reflective material has been applied to one of the broad surfaces of the blanket material. The reflective material, such as aluminum foil, functions as a barrier to radiant heat transfer.
One of the problems with the above noted structures is that when reflective surfaces of the foil engage another surface, such as the fiberglass of an adjacent insulation blanket or the adjacent gypsum board or other wall structure, the foil loses at least some of its ability to reflect heat. A space, such as a dead air space, must be maintained adjacent the foil so the foil can function as an effective heat reflector.
Another problem with the use of reflective surface in combination with other insulation materials is that if the surface should become dirty from an accumulation of dust, trash, fibers, vapor, etc., the reflective sheet looses its ability to reflect radiant heat.
It is this problem that the invention addresses.
Briefly described, the present invention comprises an improved heat insulation assembly for placement in and for becoming a part of a building structure, for insulating the structure from conduction, convection and radiation heat transfer through the wall structures of the building. This includes vertical walls, ceilings, roofs, floors and other structures that separate interior temperature controlled spaces from outside uncontrolled temperature spaces, generally referred to herein as xe2x80x9cwall structures.xe2x80x9d In the disclosed embodiment radiant heat insulation is used, either alone or in combination with other types of heat insulation. The radiant heat insulation includes heat reflective sheet material, such as radiant heat reflective metal foil, radiant heat reflective metalized plastic sheet material, and plastic material coated with reflective substance such as metal. Typically, the foil and other radiant heat reflective sheet materials are silver in color or other efficient radiant heat reflective color. The reflective surface of the sheet is maintained in a spaced relationship with respect to the next adjacent structure, and is enclosed in a space that protects the reflective surfaces of the reflective sheet from the accumulation of dirt, dust, insulation fibers, vapor and other things that would occlude or diminish the reflective properties of the reflective surface of the reflective sheet.
In one embodiment of the invention, a pair of support sheets are arranged in superposed relationship having a lattice of seams formed there between to create an array of gas filled bubbles or cells to form a xe2x80x9ccell blanket.xe2x80x9d A radiant heat reflective sheet is placed in each of the cells between the support sheets. The array of cells extends across the length and breadth of the cell blanket with the reflective sheets positioned in the cells so as to form a substantially continuous layer of radiant heat reflective sheet material about the length and breadth of the blanket. Preferably, the cells formed by the superposed support sheets of the cell blanket will be relatively large in area in comparison with the area occupied by the seams between the cells. For example the cells may be 12 inches square and the seams less than one inch wide. The cells are proportioned to be only slightly larger than the reflective sheets. This results in the area occupied by the seams in the superposed support sheets to be relatively small in comparison to the area occupied by the reflective sheets. Also, the smaller radiant heat reflective sheets versus the larger breadth cells avoids having the reflective sheets extend into the seams at the perimeters of the cells and, therefore, avoids the likelihood of conduction heat transfer from one side of the blanket to the other side of the blanket through the reflective sheets.
Another embodiment of the invention features a pair of reflective sheets positioned in each cell of the cell blanket, with the reflective sheets being spaced from one another by adhesion of the sheets to the opposed panels of the cell, so that the air in the cells maintains an open space between the reflective sheets in each cell. By maintaining the space between the radiant heat reflective sheets of each cell, the reflectability of the sheets is maintained. Also, by placing the radiant heat reflective sheets inside a closed cell, the likelihood of dust, dirt, insulation fibers and other undesirable items reaching the reflective surfaces of the radiant heat reflective sheets is substantially reduced, thereby maintaining the reflectivity of the sheets and prolonging the lifetime of the effective insulation qualities of the cell blanket The closed cells also avoid the entry of vapor into the cells so that acidic vapor or other chemicals carried by the vapor will not contact the reflective surfaces, thereby avoiding rust and corrosion of the reflective surfaces.
While the placement of individual reflective sheets in the cells of the blanket without extending them into the seams of the blanket helps to avoid conduction heat transfer through the blanket, a more expedient manufacturing procedure for producing a heat reflective cell blanket is to apply a large sheet of heat reflective material to the cell blanket that extends across several cells and the intersecting seams in the support sheets. While the insulation against conduction heat is reduced, the reflective sheet can be spread across a larger area of the cell blanket.
Another embodiment of the invention is a cell blanket with at least one of its support sheets being formed of metalized plastic sheet material having its opposed surfaces reflective. This provides reflective surfaces facing both inwardly and outwardly of the cells formed in the blanket. The inwardly facing reflective surface is protected from occlusion and contact by foreign objects, as described above. The outwardly facing reflective surface provides for radiant heat reflection as long as it retains its reflectivity, and this blanket likely will be used in situations where the likelihood of occlusion of the outer surface is not expected.
Another embodiment of the invention is the use of a metalized polyester film applied to the interior of a support sheet.
The last described constructions avoid having separate heat reflective sheets positioned in each cell between the support sheets of the cell blanket and retain the features of space maintained adjacent the interior reflective surfaces and the protection of the reflective surfaces from accumulation of dirt, dust, fibers, vapor, etc. to avoid occlusion of the reflective surfaces.
While the radiant heat reflective cell blanket provides the capacity for reflection of radiant heat, the gas within the cells and the support sheets also provide insulation against convection and conduction heat transfer.
The seams formed in the support sheets can be produced by heat fusion when the support sheets are formed of heat fusible material, such as polyester, polypropylene. In the situations when the fusion of the layers of material is not practical, adhesive bonding of the seams is possible.
The radiant heat reflective cell blankets disclosed herein can be included in various combinations with other heat insulation structures. For example, the blankets can be mounted in superposed relationship at one or both of its side surfaces with a fiberglass blanket, thereby providing the combination of radiant heat insulation by the radiant heat reflective cell blanket as well as additional conduction and convection insulation provided by the fiberglass blankets. This combination of heat insulators is suitable for use in roofs, walls, attics, floors, and in most places of dormant activity requiring heat insulation.
Another embodiment of the invention is the combination of the above described cell blanket with gypsum board or foam board or other board that forms the interior walls of a building structure. The cell blanket can be applied to one or to both surfaces of the board, or the cell blanket can be positioned between a pair of boards
Another embodiment of the invention is the use of the above described heat reflective cell blanket in combination with both a fiberglass blanket and a foam, gypsum or other board in an external wall structure of a building.
Yet another embodiment of the invention is the placement of the heat reflective cell blanket in an attic structure, either on top of the preexisting fibrous insulation, or by placement of the cell blanket adjacent the ceiling board and the fiberglass insulation that would be laid atop the heat reflective cell blanket. The cell blanket can be added to many types of pre-existing insulated structures.
Another embodiment of the invention is the use of multiple layers of the heat reflective cell blanket. This provides not only the multiple layers of the blanket insulation but also the dead air trapped between the cell blankets.
All the embodiments of the invention provide a layer of radiant heat reflective sheet material having its reflective surface protected from the accumulation of dirt, dust, insulation fibers, vapor etc. that would occlude, tarnish or reduce the reflective capacity of the sheet material, together with a space maintained at the face of the heat reflective sheet so as to preserve the reflective abilities of the sheet.
Thus, it is an object of this invention to provide an improved heat reflective blanket for placement in a wall structure or other portion of a building structure for the purpose of shielding the building structure from the transfer of radiant heat.
Another object of this invention is to provide an improved radiant heat reflective cell blanket for placement in a wall structure in combination with other heat insulation materials, such as fiberglass blanket insulation, foam board, and other conventional structures of heat insulated wall structures.
Another object of this invention is to provide heat insulation material for application to a wall structure of a building, utilizing a radiant heat reflective cell blanket that includes radiant heat reflective sheet material placed in the cells of a cell blanket so that the cells protect the reflective material against the accumulation of dust, dirt, fibers, vapor and other things on the surface of the sheet, and for maintaining a space adjacent the reflective surface of the sheet.
Other objects, features and advantages of this invention will become apparent upon reading the following specification, when taken in conjunction with the accompanying drawings.